The plant species Lycopersicon pennellii Corr. (also known as Solanum pennellii Corr.) is known to inhabit the extremely dry, lower, western slopes of the Central Peruvian Andes. This species has a rather wide geographic distribution that extends from El Horador (Depto. Piura) in northern Peru to Camana (Depto. Arequipa) in southern Peru. The autecology of these native populations is such that often the only other vegetation growing in close proximity to Lycopersicon pennellii plants are cacti and bromeliads.
As a plant species, Lycopersicon pennellii is morphologically intermediate between potato and tomato. However, since Lycopersicon pennellii is interfertile in controlled pollinations with the cultivated tomato, it is commonly grouped with other wild species of tomato. Yu (1972) and Rick (1973) have shown that among tomato species, Lycopersicon pennellii leaves have a unique and special ability to withstand desiccation. They also point out that Lycopersicon pennellii distinguishes itself from other Lycopersicon species, except Lycopersicon chilense, in its ability to withstand conditions of extreme drought.
Both native, greenhouse and field populations of Lycopersicon pennellii have oily glands that produce a sticky exudate which covers the surfaces of Lycopersicon pennellii leaves, stems, peduncles, calyxes and fruits. An analysis of lipids in the leaves of Lycopersicon pennellii by Ermakov (1980) shows that the leaves have a high lipid content. The Ermakov study further shows that the Lycopersicon pennellii leaf lipids contain some 15 fatty acid components, the predominant ones being saturated fatty acids, especially capric acid (C10:0). In cultivated tomato leaves, e.g., the cultivar Gruntovy Gribovsky, Ermakov states that unsaturated fatty acids, especially linolenic acid (C18:3), usually prevail.
In addition to analyzing total leaf lipids, Ermakov also analyzed lipids isolated from the glandular hairs of Lycopersicon pennelli leaves. His results show that the glandular hair lipids are mainly polar and that they comprise over 70 percent of the total lipids in the leaves. In comparing the glandular hair lipids with well known plant galactolipids (for which a high concentration of unsaturated fatty acids is characteristic), Ermakov points out the glandular hair lipids have a high concentration of saturated fatty acids, especially those with a relative molecular size or length of up to C14.